Sleep Debt Calculator
How much sleep you have accumulated a deficit of.
Accumulated sleep debt
10.5 hours
over 7 days
A debt this size does not clear with one long weekend. Studies find attention and metabolic markers do not fully normalise after chronic restriction.
How the Sleep Debt Calculator works
Sleep debt is the running total between what you need and what you actually get. It accumulates quietly — an hour short each weeknight is five hours by Friday — and the performance cost tends to be larger than how tired you feel.
Not medical advice. This calculator gives a general estimate, not medical advice. It cannot account for your individual health, medical history, or medication. Talk to a qualified healthcare professional before acting on any result.
Frequently asked questions
Can you catch up on lost sleep?
Partially. One or two extra hours over a weekend recovers some cognitive performance, but studies find attention and metabolic markers do not fully normalise after chronic restriction. Larger debts need several consistent nights, not one long lie-in.
How much sleep do adults actually need?
7-9 hours for most adults, per the National Sleep Foundation. A small minority genuinely function on 6, and far more people believe they are in that minority than actually are — self-assessed alertness is a poor guide once you are chronically short.
What does sleep debt do to you?
Reduced attention and reaction time, impaired memory consolidation, worse glucose regulation, increased appetite through changes in leptin and ghrelin, and lowered immune function. Reaction times after 17-19 hours awake are comparable to being over the legal drink-drive limit.
Is a nap useful?
Yes, in the right form. A 10-20 minute nap improves alertness without leaving grogginess. A 90-minute nap completes a full cycle and helps memory. The 30-60 minute range is the one to avoid — long enough to enter deep sleep, too short to finish it.